Counting chamber



Dec. 5, 1939. Q R BROWN HAL 2,182,467

COUNTING CHAMBER Filed June 8, 1938 A INVENTOR C/au deffirown re ae r'v'aEW'fso :1,

ATTORNEY Patented Dec. 5, 1939 STATES COUNTING cum/man Application June 8, 1938, Serial no. 2121.569

3 Claims.

The object of this invention is to provide improvements in so-called counting chambers, and particularly in means for securing the cover slip in fixed operative position.

The counting chamber involved is that, which is designed for use in counting the number of co-rpuscles in'a given specimen of blood, or for counting the cells in a given sample of spinal fluid, and similar uses. Heretofore, the cover slip has been retained in operative position while the device is in use merely by means of its exceedingly light weight and consequent meager friction, in addition to the adhesion or capillary attraction efiected by the presence of the fluid under observation.

Another object is to provide an improved clamp, preferably used in pairs, for more positively securing the cover slip in place, and prevent it from shifting its position even to the slightest degree, for as long a period as may be necessary, and to make such clamp of light weight yet rugged construction, and of inexpensive manufacture. I

A further object is to provide means carried by the chambers base for securing the clips thereto, so that the said clips are laterally movable with respect to said base, as well as being completely detachable therefrom as for cleaning, and so constructed that each bears with equal pressure upon spaced portions of the cover slip, while the clips of each pair are preferably positioned upon transversely opposite edge portions of said base.

Withv the objects thus briefly stated, the invention comprises further details of construction and operation, such as are hereinafter fully described in the following specification, when read in conjunction with the accompanying drawing, in which Fig. l is a top plan View of an improved counting chamber comprising one embodiment of the invention; Fig. 2 is a longitudinal section on the line 2-2 of Fig. 1; Fig. 3 is a transverse section on the line 33 of Fig. 1; Fig. 4 is an enlarged fragmentary portion of the device as shown in Fig. 3. the section of Fig. 4,

however, beingtaken slightly to one side of the' plane of the section of Fig. 3; and Fig. 5 is an enlarged side elevation of one of the said clips in its most depressed position.

Referring to the drawing, one embodiment of the invention is shown as comprising a preferably rectangular base l, of any suitable material, and provided with a preferably rectangular, centrally positioned aperture 2, bounded upon three sides by a planular shoulder 3, upon which rest corresponding portions of the periphery of any well-known type of properly lined counter glass 3 which does not comprise a part of the present invention, but is characterized by an upper planula'r surface 5", crossed by a pair of spaced longitudinally extending fiat-bottomed grooves 6, which at their central portions are relatively quite shallow and intersect a. transversely e5;- tending fiat-bottomed groove 'l. Transversely considered, the laterally opposite edges 8 of the counter glass slide longitudinally into, opposed dove-tail grooves 9. in said base, thereby preventing said glass from rising away from shoulder' 3, and restricting it to longitudinal movement in one direction. The cover glass 4' is normally maintained in operative position and prevented from longitudinal movement by means of a removable block lll, which rests in a cut-away portion H at one end of the base i, and is normally secured in fixed clamping position by means of a screw or the like I 3;

Normally resting upon the surface 5 and extending across said grooves is a relatively thin glass cover slip [4, which is normally secured in operative position by means of an improved form of clamp or clip which comprises the present invention. Extending longitudinally inwardly from the opposite ends of the counter glass t and between the spaced grooves 6, are surfaces l5 of said counter glass which decrease in depth with respect'to the plane of the surface 5, as they progress inwardly towards the transverse groove I the innermost adjacent portions of said surfaces lying in the same plane; and presenting a pair of substantially square areas l6, which are provided with minutely spaced microscopicparallel lines. spinal fluid, or other liquid placed upon either or both of the outer opposite end portions of the surfaces t5 engage the under surface of the under slip l4 and are drawn by capillary attraction into the relatively shallow space between said cover slip and the square areas it, so that when that portion of the liquid so positioned is viewed through a high-powered microscope, the corpuscles, cells, or other relatively solid particles, may be counted by comparison with the minutely spaced parallel lines, with which the surface areas iii are provided. However, with the construction described to this point, it is obvious that the cover slip M is held in operative position by nothing more than the meager adhesion between its lower surface and'the surface 5 upon which it directly rests, so that only a relatively slight jar or draft of air is necessary to dislodge In using this device, a drop of blood,

said slip and defeat the accuracy of any count which may be in progress at the time.

With these deficiencies in mind, the central laterally opposite portions of the base I have been provided with any suitable type of guides 11, provided in this instance with spaced parallel, inwardly directed flanges l8, said guides being secured to said base by any suitable means, such for instance, as the bolts 19 or the like, but it is to be understood that instead of said guides comprising initially separate members, there may be substituted for them merely spaced parallel dovetail or other suitable form of flanges or shoulders, formed integrally in said base in wellknown manner.

The form of improved clip here shown comprises a plate 20, which is adapted to be slidably received and supported by and between the flanges l8, and supports a pair of spaced, upwardly extending lugs 2|, between which extends a shaft 22, forming upon its opposite ends bearings for the spaced depending shoulders 23, carried by an angularly movable clip member 24, which in addition comprises a rear finger-engageable extension and a forward extension 26, which preferably tapers forwardly and merges into a depending extension 21, through which extends a shaft 28, the rear end of which shaft is supported by a lug 29, which comprises a depending integral extension of the central portion of the member 24. Upon the forward, freely extending outer portion of the shaft 28 there is pivotally mounted a yoke 30, comprising laterally spaced, depending fingers 3|, which normally engage with equal pressure upon the upper surface of the cover slip l4, as'shown in Figs. 1, 2, and 3. Each of said clips being normally maintained in operative position, as is shown by means of a suitable spring 32, coiled about the shaft 22, and having its opposite free ends in engagement with the plate 20 and the finger-engageable extension 25, respectively, thereby tending to force the clip member 24 towards the extreme inoperative position shown in Fig. 5.

In the operation of this device, the counter glass 4 is fixedly secured in the base I, as shown in Figs. 1, 2, and 3, and the cover slip placed in position thereon, where it is yieldinglysecured by means of a pair of the improved clips, as also shown in said figures, thereby operatively securing said cover slip in fixed substantially unyielding position, except when it is desired to remove the same for purposes of cleaning the apparatus, in which case the clip extensions 25 are depressed and the clips slid in laterally opposite directions outwardly, or at least held in retracted position until the slip is removed from beneath them, whereupon said slip and counter glass can be cleaned in accordance with accepted practice. Furthermore, while one particular form of the improved clip is herein described and illustrated, it is to be understood that there are various ways in which the same can be constructed, so as to function to all intents andpurposes the same as herein described, so that many such modifications can be made in the construction of said clip without. departing from the spirit of the invention, as defined by the appended claims.

And still furthermorait will be obvious that the improved clip is equally well adapted for use with the particular type of glass shown in the drawing, or with a glass in which the longitudinal axis of the H shape of related grooves extends transversely instead of lengthwise of the said glass. In fact, the construction, function and operation of the clip per se is but little affected by the type, kind or structure of the counter glass as a separate element, or its exact position upon the supporting base.

Having thus described our invention, what we claim as new and desire to protect by Letters Patent of the United States is:

l. The combination of a base, an element removably positioned upon said base, and a clip comprising a base, guide means carried by said first base to slidably receive and operatively position said clip base, an angularly oscillatable member pivotally mounted upon the second base, a yoke having a pair of spaced'depending fingers and pivotally carried by said member, the axes of the pivotal connections being angularly disposed and resilient means to yieldingly position said member angularly with respect to said second base, and to cause said fingers to contact said cover slip with equal pressure, to prevent the same from shifting laterally upon and with respect to or away from said glass.

2. The combination of a base having laterally spaced parallel shoulders, an element positioned upon said base, and a clip comprising a base positioned slidably between said shoulders, an oscillatable member pivotally carried by said lastmentioned base, a yoke having a pair of spaced depending fingers and pivotally carried by said member, the axes of the pivotal connections being angularly disposed, and resilient means to yieldingly position said member with respect to said second base, and to cause the fingers to contact said element with equal pressure, to prevent the same from shifting laterally upon and with respect to said first base.

3. The combination of a base having a guideway, an element positioned upon said base, and a clip comprising a base slidably positioned in said guideway, an oscillatable member pivotally carried by said last-mentioned base and having an arm, a yoke having a pair of spaced depending fingers and pivotally carried by said arm, the axes of the pivotal connections being angularly disposed, and resilient means to yieldingly position said member with respect to said second base, and to cause the fingers-of the yoke to contact said element with equal pressure, to prevent the same from shifting laterally upon and with respect to said first base.

CLAUDE P. BROWN. FREDERIC H. WILSON. 

